Sharpening device for rotary cutters.



A. R. LUSOHKA.

SHARPENING DEVICE FOR ROTARY CUTTERS.

APPLICATION FILED APR.1'5, 1912.

1 06() 9 1 6. Patented May 6, 1913.

2 SHEETS-SHEET 1.

' A filzwc" M M M5226 Aitorngyp frame A and is locked in position by the UNITED STATES FATENT QFFTQE,

AUGUST R. LUSCHKA, OF CHICAGO, ILLINOIS, ASSIGNOR TO AMERICAN SLICING MACHINE COMPANY, OF CHICAGO, ILLINOIS, A CORPORATION OF NEW YORK.

SHARPENING DEVICE FOR ROTARY CUTTERS.

Specification of Letters Patent.

Patented May 6,1913.

T 0 all whom it may concern Be. it known that I, AUGUST R. Loser-nu, a citizen of the United States, residing at Chicago, in the county of Cook and State of Illinois, have invented a certain new and useful Improvement in Sharpening Devices for Rotary Cutters, of which the following is a specification.

My invention relates to improvements in sharpening devices for rotary cutters and is i illustrated diagrammatically in one form in the accompanying drawings, wherein Figure 1 is a side elevation with parts in section; Fig. 2, a detail side elevation of one of the grinding means and housing therefor; Fig. .3, a detail end view looking toward the right on Fig.1; Fig. 4, a section along the line l4 of Fig. 1; Fig. 5, a section along, the line 5-5 of Fig. '1; Fig. 6, a section.

along the line 6-6 of Fig. 1; Fig. 7, a de-! tail diagrammatic plan view of the cutter and grinding wheels. o

Like parts are indicated by like letters throughout the several figures.

The usual slicing machine base A in which is mounted the drive shaft A carrying the crank wheel A supports the reciprocating table A on theguide rail A The vertical chain housing and knife support A is pivotally mounted on the cap-screw A on the bolt or cap-screw A" in slidable engagement with the curved slot A The drivechain A which is inclosed within the housing A rides upon a sprocket A driven from the drive shaft A by any suitable means and drives the sprocket A on the shaft A which shaft is vrotatably mounted in the upper end of the housing A".

The concavo-convex rotary cutter or knife B is rigidly mounted on the shaft A and has peripherally disposed the truncated conical knife surface B terminating in a peripherally disposed cutting edge. The vertical arm or support B 7 projects upwardly from the top of the housing A and carries pivotally mounted thereon and held in posit-ion by 'the thumbscrew B the grooved knife guard B which conforms substantially in curvature to the knife and is held rigidly in position at its lower end against the housing A by the ,thumbscrew B engaging the hook B The knife guard 13 is provided at its lower end with the horizontal projection 13 which extends forwardly from the knife toward the reciprocating carriage B The knife guard B has on its lower side adjacent the housing A the downwardly and outwardly-disposed and extended pocket C having an inclined flat wall C projecting outwardly and away from the concave side of the knife. This pocket is open toward the convex side of the knife and the'opening is closed by the two-part portion or door C C the two-parts being pivoted at C on the wall C and limited in their motion together by the pin C in thelwall C These parts C C are slotted so as to form the oval opening G into the interior of the pocket when they are brought together.

The vertical armor support 13 which projects upwardly from the top of the housing A is provided at its uppermost extremity with the thumbscrew D upon which is pivoted a shield D slotted at D and having a flat side D in opposition to a fiat end D on the knife guard 13*. This shield forms in effect a continuation of the slotted knife guard but has an open side at the front of the knife. The'cap D which is pivotally mounted on the thumbscrew D is slotted at l) in continuation of the slot 1) and closes the open upper portion of the guard or shield D The set-screw l) in the shield D serves to hold the cap in fixed position in such manner that the shield and cap may be together swung back from the knife or the cap alone may be swung back leaving the shield in position.

The shield D carries the outwardly pr0 jec'ting split lug E in which is slidably androtatably mounted the rod E adapted to be clamped by the screw E The rod E terminates in the square split head E in which is held the lug E clamped in position by the screw E and carrying the sleeve E The shaft E is rotatably and slidably mounted in the sleeve E and carries at one end rig idly mounted thereon the cupped grindlng wheel E having the convex-grinding surface E in opposition to the smooth front edge of the knife. The helical spring E surrounds a shaft E and is interposed between the grinding cu and the sleeve to yieldingly force the grinding cup or wheel away from the knife. The handle E whichis rotatably mounted on the other end of the shaft E may be used to manually force the cupped grinding wheel toward the knife,

, ference.

The slot in the shield and cap is provided in order to permit an adjustment of the holding. and supporting means for the grinder and in order to permit the grinder to be positioned accurately with respect to the knife without in any way interfering or being interfered with by the housing, shield, cap, etc.

The housing A carries at its top the bearing sleeve F in which is rotatably mounted the shaft F The lever F is provided at its lower end with the square split head F adapted to be clamped on the shaft F by means of the screw F. This lever projects upwardly to a point adjacent the member E. The shaft F has at its other end the square split head F in which is rotatably and slidably mounted the rod F adapted to be clamped in position by the screw F The rod F terminates at its lower end in the split head F in which is rotatably held the lug F 9 clamped in position by the screw F The lug F carries the sleeveZF in which is rotatably mounted the shaft F The shaft F is provided with the annular groove F which is slidably engaged by the set-screw F in the wall of the sleeve F The cupped grinding wheel F which is provided with the convex cutting surface F in opposition to the conical surface 18 on the knife is rigidly mounted on the shaft F The grinding wheel F is located within the pocket C and the supports for the grinding wheel enter the pocket through the oval opening C. This grinding wheel and its supports are so disposed that it tends, when acted on freely by the force of gravity, to swing away from the knife and therefore this grinding wheel is normally completely out of contact with the knife but located within and inclosed and protected by the pocket which forms in efiect a continuation of orannex to the knife housing.

I have shown the axisof rotation of each of the grinding wheels inclined outwardly from the knife and also inclined backwardly toward the direction of rotation of the knife in such manner that they are neither perpendicular to the surface to be ound nor arallel with the axis of rotation of the ife. The result of this .is that but one side of the grinding cup contacts the knife and the-rotation of'the knife, or cutter when in engagement with the grinding cup tends to cause the cup to rotate. However, the rotation of these two parts causes such a lateral displacement with respect one to the other that the edges of the knife are ground and that the grinding surfaces assume a convex shape.

It will be understood that. the larger grinding wheel in engagement withthe conical portion of the knife is thewheel which does the grinding for sharpening purposes and the function of the smallergrinding wheel is merely to take off the bur or feathered edge which is, of course, formed by the grinding point of the conical portion of the knife. The two grinding Wheels, of

course, are absolutely independent in their Although the work may equally well be done by first grinding down the outer conical surface and then bringing the smaller wheel into opposition to the fiat surface to take off the bur, it will be noted that the supports of both of the grinding wheels are such they have a universal annular adjustment so that the position of the axis of rotation of the grinding wheel may be set by the operator wherever desired and the setting whichl have shown, while for a knife the contour of which is the same as the knife I have shown in my preferred setting, still for other knives or even for the same knife when different shaped cutting edges are desired, the setting might be materially altered without departing in any sense from the spirit of my invention. It will be obvious, therefore, that many changes might be made in the size, shape and arrangements of parts and in the setting and adjusting of the different features without departing materially from the spirit of my invention and I wish, therefore, that my drawings be regarded'as in a sense diagrammatic. 7

In Fig. 1 the wheel B is shown with the curved spiral lines K curved spirally outward in a direction the same as the direction of rotation. These are meant merely as a diagrammatic showing of the way in which the knife is ground. An inspection of the knife when ground by my device shows these spiral'markings on either side of it, the marking on each side pointing forward as indicated. This is the result of the grind ing action and results in giving the knife what is in effect a microscopic saw tooth edge which adds very greatly to the efficiency of the cutting operation. This result is obtained because of the arrangement of the grinding wheels wherein they rotate in opposite directions from the cutting wheel and it is necessaryin order to produce this result that each of them rotate in the oppopointing grooves, which grooves terminate in microscopic saw teeth that the best cutting result is obtained. This result is obtained, it will be observed, by causing the cutting wheel. to come in contact with the grinding wheel on the back side of the grinding wheel, but at a point inside of the axis of rotation thereof and it is this arrange ment which produces the desired result. In other words, in order to produce a maximum cutting efliciency, it is necessary that the grinding action take place alonglines inclined backwardly from the cutting edge, thus forming on both sides of the cutting edge these almost microscopic lines which terminate in forwardly overhanging sawteeth .to facilitate the cutting. 'It will be noted that these lines do not extend very far in from the cutting edge, and this is because the grinders are not expected to grind off the entire bevel of the knife, but merely to keep sharp the cutting edge, since the truing up of the knife by means of grinding down the bevel, which must be done occasionally, as the knife wears out, must be done by special movement, since it is too heavy a disk for the relatively small grinding wheels indicated. I have shown a larger cupped grinding wheel as having a slightly convexed surface, but it is of'eourse evident that this is by no means essential and depends entirely upon the setting of the wheel with respect to the cutting edge of the knife, and all that is required in either case is that the knife grind the wheelin .the lines as indicated.

The use and operation of my invention are as follows :VVhen a rotary cutter is to be sharpened this must be done by first grinding down the truncated conical cutting edge or surface but this grinding down will have to be done by the rotation of the cutter and the pressure of the grinding wheel upon the unsupported cutting edge will cause a bur to form upon the other side, and this bur must be ground off before the cutter will have a sharp cutting edge. In sharpening a cutter, therefore, the operator first seizes the swinging lever in his hand and pulls it out. This presses the large grinding wheel against the conical cutting edge and causes it to be ground off by the wheel the setting of the wheel being such that the rotation of the cutter causes the wheel to rotate and slide across the cutting edge thus grinding it off. The operator then simultaneously or later presses forward the hand button on the shaft of the smaller grinding wheel thus pressing that wheel against the opposed side of the cutter and smoothing off the bur and grinding the edge down upon the opposed side thus giving the sharp cutting edge desired. The position of the end of the lever and the hand button is such that the operator may seize them together in one hand and by a single movement cause them both to operate or he may operate them independ- Under ordinary circumstances he entlv; will probably operate them independently grinding first and afterward takingofi' the bur.

Themovement of the two grinding wheels toward the cutter is limited only by their pressure upon the cutter and when once they reach the cutter they commence their work. The setting of the grinding wheels and their relation'to'the cutter is such that they are self-leveling and therefore the same grinder may be used to' grind the cutter without any further adjustment once the proper adjustment has been made. This-proper adjustment is made by rotating the two vertical supporting rods and clamping them into suitable position and by then rotating the two holding sleeves and clamping them into suitable position or vice versa. In any event, the two adjustments in planes at right angles one to the other enable the operator to fix the axis of rotation at any desired angle with respect to the knife, the knife surface,

the axis of rotation of the knife or any other point so that the maximum eflect may be had bythe grinding wheels.

I claim:

1. A sharpening device for rotary cutters having grinding wheels in opposition to the cutting edge and a peripherally disposed combined guard and housing inclosing the cutting edge and thegrinding wheels.

2. A sharpening device for rotary cutters.

and grinding wheels in opposition to the cutting edge and a peripherally disposed guard therefor and pockets continuous with said guard to inclose the grinding wheels.

3. A sharpening device for rotary cutters having grinding wheels in opposition to the cutting edge and a substantially semi-circular guard inclosing the cutting edge of the cutter for substantially half its length and pockets in said guard for the grinding wheels, said pockets'being disposed one at either end of the guard.

4. A sharpening device for rotary cutters having grinding wheels in opposition to the cutting. edge and a peripherally disposed guard, a pocket pivotally mounted on one end of said guard to inclose one of said grinding wheels.

A sharpening device for rotary cutters having grinding wheels in opposition to the cutting edge of a peripherally disposed guard, a pocket pivotally mounted on one end of said guard to inclose one of said grinding wheels, said pocket having a removable cover said cover being plvotally mounted on the pocket.

6. A sharpening device for rotary cutters having grinding wheels in opposition to the cutting edge and a peripherally disposed guard, a pocket pivotally mounted on one end of said guard to inclose one ofsaid grinding wheels and a support-carried bysaid pivotally mounted pocket for one of said grinding wheels.

7. A sharpening device for rotary cutters having grinding wheels in opposition to the cutting edge and a peripherally disposed guard, a pocket pivotally mounted on one end of said guard to inclose one of said grinding wheels, said pocket having a removable cover said cover being pivotally mo em mounted on thepocket and a support carried by said pivotally mounted pocket for one of said grinding wheels.

8. A sharpening device for rotary cutters having grinding wheels in opposition to the cutting edge with a peripherally disposed guard therefor, a pocket continuous with said guard to inclose one of said grinders said pocket being cut away on one side and provided with a pivotallymounted cover to inclose said cut-away portion.

Signed at Chicago, Illinois this 11th day of April 1912.

AUGUST R. LUSCHKA.

Witnesses FRANCIS W. PARKER, J r., LULU JORDAN. 

